Articles

Articles are a collaborative effort to provide a single canonical page on all topics relevant to the practice of radiology. As such, articles are written and edited by countless contributing members over a period of time. A global group of dedicated editors oversee accuracy, consulting with expert advisers, and constantly reviewing additions.

1,237 results found
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Vestibule (disambiguation)

A vestibule is an anatomical term and refers to a small cavity at the proximal end of a tube. It may refer to: vestibule (aorta) vestibule (ear) vestibule (larynx) vestibule (mouth) vestibule (nose) vestibule (esophagus) vestibule (vulva) History and etymology Vestibule derives ultimate...
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Vicarious contrast material excretion

Vicarious contrast material excretion (VCME) defines excretion of water-soluble contrast material in a way other than via normal renal excretion. The most common vicarious excretion of water-soluble contrast material is via the liver, resulting in increased bile density seen in the gallbladder. ...
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Videofluoroscopic swallow study

Videofluoroscopic swallow studies (also often called modified barium swallow studies) are a variation on traditional barium swallow studies. Although typical barium swallow studies / esophagrams evaluate the pharynx, the goal in these studies is to even more closely evaluate the oral cavity, pha...
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VIPoma

VIPomas are a very rare type of pancreatic endocrine tumors that secrete, and get their name from, vasoactive intestinal peptide (VIP). The clinical syndrome resulting from these tumors is commonly known as WDHA syndrome, as an acronym of the cardinal symptoms of watery diarrhea, hypokalemia, an...
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Virgin abdomen

Virgin abdomen is used to describe the abdomen of a patient who has never had any surgical procedure on their abdomen. It is usually used in the context of someone presenting with an acute small bowel obstruction and whether adhesions might be the underlying etiology. The conventional wisdom be...
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Vitamin B3

Vitamin B3 (niacin or nicotinic acid) is a water-soluble vitamin, part of the vitamin B complex, that is an important part of the coenzyme nicotinamide adenine dinucleotide (NAD+) which is involved in many reactions of cellular metabolism. Related pathology pellagra is the clinical syndrome of...
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Von Hippel-Lindau disease

Von Hippel-Lindau (vHL) disease is characterized by the development of numerous benign and malignant tumors in different organs (at least 40 types 1) due to mutations in the VHL tumor suppressor gene on chromosome 3. Epidemiology The disease is rare with an estimated prevalence of 1:35,000-50,...
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Walled-off pancreatic necrosis

Walled-off pancreatic necrosis (WOPN) is a late complication of acute pancreatitis, although it can occur in chronic pancreatitis or as a result of pancreatic trauma. Differentiation of WOPN from pancreatic pseudocyst is essential because management differs. WOPN may need aggressive treatment to...
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Wandering spleen

Wandering spleen is a rare condition in which the spleen migrates from its usual anatomical position, commonly to the lower abdomen or pelvis. Epidemiology Wandering spleen is rare, with a reported incidence of <0.5%. Diagnosis is most commonly made between ages 20 and 40 years and is more co...
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Water siphon test

The water siphon test may be performed as part of a barium swallow to assess for gastro-esophageal reflux. It is performed in the supine RPO position with the patient drinking water continuously. The test is said to be positive if there is visible barium reflux in the esophagus, and is more sens...
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Weight loss

A clinical presentation of weight loss is extremely common and often a source of marked anxiety for the patient. The commonest cause of unintentional weight loss (UWI) is gastrointestinal tract disease, and not malignancy. Terminology The published literature lacks a consistent definition of w...
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Whipple disease

Whipple disease is a rare infectious multisystem disorder caused by the actinobacteria Tropheryma whipplei. Epidemiology The incidence of Whipple disease is not truly known, one Swiss study estimated it at approximately 1 per 1.5 million per year 7. The peak age for presentation is in the fif...
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Whipple disease (gastrointestinal manifestations)

Gastrointestinal manifestations are a key component of Whipple disease.  The gastrointestinal manifestations of Tropheryma whipplei are also known as intestinal lipodystrophy. Pathology Extensive infiltration of the lamina propria with large macrophages infected by intracellular T. whipplei ca...
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Whipple procedure

The Whipple procedure (or partial pancreaticoduodenectomy) is considered the definitive surgical operation to resect carcinoma of the head of the pancreas, periampullary carcinoma, or duodenal carcinoma 1. Procedure In the procedure, the head of the pancreas and adjacent duodenum is resected. ...
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Whipple triad

Whipple triad is the clinical presentation of pancreatic insulinoma and consists of: fasting hypoglycemia (<50 mg/dL) symptoms of hypoglycemia immediate relief of symptoms after the administration of IV glucose History and etymology The triad and also the Whipple procedure were both named a...
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Whirlpool sign (mesentery)

The whirlpool sign of the mesentery, also known as the whirl sign, is seen when the bowel rotates around its mesentery leading to whirls of the mesenteric vessels.  Terminology The term whirlpool sign is used in other contexts: see whirlpool sign (disambiguation). Radiographic features It is...
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WHO classification of anal canal tumors

The World Health Organization classifies anal canal neoplasms into intraepithelial neoplasms and invasive neoplasms which are further divided to epithelial and non-epithelial tumors and secondary lesions: Epithelial tumors squamous cell carcinoma of anal canal adenocarcinoma of anal canal mu...
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WHO classification of anal margin tumors

The WHO classification of anal margin tumors or perianal skin tumors is: intraepithelial tumors Bowen disease (precursor of squamous cell carcinoma) Paget's disease (precursor of adenocarcinoma) invasive tumors squamous cell carcinoma adenocarcinoma basal cell carcinoma  verrucous carcin...
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Widening of the presacral space (differential)

Widening of the presacral space is one of the diagnostic indicators of the diseases involving pelvic pathology and rectal involvement. It is ideally measured on barium studies at the level of S3/4 disc level on lateral radiographs and the normal value of the presacral space is <15 mm in adults.​...
Article

Windsock sign (duodenal web)

The windsock sign is a typical appearance of a duodenal web (intraluminal duodenal diverticulum) on upper gastrointestinal contrast series which consists of an intraduodenal barium contrast-filled sac that is surrounded by a narrow lucent line (web or intraluminal mucosal diaphragm) which is wel...
Article

Wound dehiscence

Wound dehiscence is a surgical complication whereby there is rupture of a wound along the surgical scar (dehiscence, refers to "splitting open"). This may occur on the skin surface, or along a deeper suture line. Clinical presentation Presentation may be with pain (e.g. sternal dehiscence), or...
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X-marks-the-spot sign (large bowel volvulus)

The X-marks-the-spot is a sign of complete bowel volvulus and refers to the crossing loops of the bowel at the site of the transition. It has been reported to improve diagnostic confidence in detecting cecal and sigmoid volvulus. This is in contrast to the split-wall sign which indicates partial...
Article

Zebra spleen

Zebra spleen, also referred to as psychedelic spleen or more correctly inhomogeneous splenic enhancement, refers to the transient heterogeneous parenchymal enhancement of the spleen during the arterial or early portal venous phases of contrast enhancement in CT, MRI, or ultrasound imaging. It i...
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Zenker diverticulum

Zenker diverticulum, also known as a pharyngeal pouch, is a posterior outpouching of the hypopharynx, just proximal to the upper esophageal sphincter through a weakness in the muscle layer called the Killian dehiscence. Epidemiology More than 50% of the affected patients present in 60-80 years...
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Zinc toxicity

Zinc toxicity (also rarely known as zincalism) is rare as the body is remarkably efficient at excreting excess zinc. Typically oral zinc poisoning manifests primarily as: acute GI symptoms: vomiting, diarrhea, abdominal pain secondary copper deficiency zinc competes with copper for absorption...
Article

Z line

The Z line in the esophagus is the term for a faint zig-zag impression at the gastro-esophageal junction that demarcates the transition between the stratified squamous epithelium in the esophagus and the intestinal epithelium of the gastric cardia (the squamocolumnar junction). The Z line is a ...
Article

Zollinger-Ellison syndrome

Zollinger-Ellison syndrome (ZES) is a clinical syndrome that occurs secondary to a gastrinoma.  Clinical presentation Diagnosis of ZES is often delayed by 5-7 years after the onset of symptoms 2.  Pathology Gastrinomas are usually multiple and typically located in the duodenum (more common) ...
Article

Zuelzer-Wilson syndrome

Zuelzer-Wilson syndrome, also known as total colonic aganglionosis, is a subset of Hirschsprung disease, in which the whole colon is aganglionic. Epidemiology It is uncommon and accounts for 2-13% of cases of Hirschsprung disease 3,7. Compared with Hirschsprung disease which has a marked male ...

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